{"library":"lodash._createaggregator","title":"Lodash Internal createAggregator Module","description":"This package, `lodash._createaggregator` v3.0.0, provides a modular build of Lodash's internal `createAggregator` function from the Lodash 3.x series. It is an internal utility primarily used by other Lodash functions to build collection methods like `groupBy` or `countBy`. The main Lodash library has since progressed to v4.x and beyond (currently v4.18.1 as of late 2024/early 2025). This specific package has not received any updates, bug fixes, performance improvements, or security patches since its original v3.0.0 release in 2015. It is exclusively designed for CommonJS environments. Due to its age and internal nature, it is not recommended for direct use in modern applications; developers should rely on the public API of the actively maintained `lodash` or `lodash-es` packages instead.","language":"javascript","status":"abandoned","last_verified":"Sun Apr 19","install":{"commands":["npm install lodash._createaggregator"],"cli":null},"imports":["const createAggregator = require('lodash._createaggregator');","const buildAggregator = require('lodash._createaggregator');","// No direct TypeScript type definitions are available or maintained for this old internal module. Consider using a custom type declaration if absolutely necessary."],"auth":{"required":false,"env_vars":[]},"quickstart":{"code":"const createAggregator = require('lodash._createaggregator');\n\n// Simulate the internal use of createAggregator to build a 'groupBy' like function.\n// createAggregator takes an 'init' function (for the initial result) and an 'accumulator' function.\nconst myGroupBy = createAggregator(\n  function() { return {}; }, // The 'init' function: provides the initial result object (e.g., empty object for groupBy).\n  function(result, value, key) { // The 'accumulator' function: adds values to the result based on the key.\n    if (!result[key]) {\n      result[key] = [];\n    }\n    result[key].push(value);\n  }\n  // A 'reducer' function (for final processing) can also be passed as a third argument, but is optional for simple aggregation like groupBy.\n);\n\nconst data = [\n  { 'user': 'barney', 'age': 36, 'active': true },\n  { 'user': 'fred',   'age': 40, 'active': false },\n  { 'user': 'pebbles', 'age': 1, 'active': true },\n  { 'user': 'fred',   'age': 40, 'active': true }\n];\n\nconsole.log('Grouped by age:', myGroupBy(data, item => item.age));\n/*\nExpected output:\n{ '36': [ { user: 'barney', age: 36, active: true } ],\n  '40': [ { user: 'fred', age: 40, active: false }, { user: 'fred', age: 40, active: true } ],\n  '1': [ { user: 'pebbles', age: 1, active: true } ]\n}\n*/\n\nconsole.log('Grouped by active status:', myGroupBy(data, item => item.active));\n/*\nExpected output:\n{ 'true': [ { user: 'barney', age: 36, active: true }, { user: 'pebbles', age: 1, active: true }, { user: 'fred', age: 40, active: true } ],\n  'false': [ { user: 'fred', age: 40, active: false } ]\n}\n*/","lang":"javascript","description":"Demonstrates how to use the internal `createAggregator` function to construct a simplified `groupBy` utility. This illustrates the factory pattern for collection aggregation, mirroring its purpose within the Lodash library's internal workings.","tag":null,"tag_description":null,"last_tested":null,"results":[]},"compatibility":null}